小菜蛾寄生性天敌的研究进展

小菜蛾已成为目前\"化学杀虫剂防治困难\"的典型害虫之一.面对此困境,利用丰富的小菜蛾天敌资源并取得持续的控制作用已成为国内外研究的热点.本文就近年来小菜蛾寄生性天敌的研究进展作一综述.     

多寄主型寄生性天敌昆虫的寄主适应性及其影响因素

寄生性天敌昆虫对不同寄主资源的适应能力是其存活和繁殖的必要条件,它们的寄主选择行为则是其重要的适应结果。多寄主型寄生性天敌昆虫虽然对某种特定寄主资源的利用效率可能不如单寄主型寄生蜂,但却有利于拓展更宽的寄主范围,因此对环境的适应能力更强,更容易在自然界维持其种群的生存。统计结果也表明多寄主型天敌的生物防治效果往往比专食性天敌更高。有时生物防治成功的关键可能并不在于所利用的天敌种类的不同,而在于天敌的不同生物型或地理宗。总结了多寄主型寄生性天敌昆虫的寄主适应能力及其影响因素。寄生性天敌昆虫不仅因地理隔离产生种群分化,也可能因寄生不同的寄主产生种群内的分化,从而更加适应寄主的生活特性和栖境条件。寄主种类、寄主发育阶段、寄主大小、寄主营养、寄主免疫反应、寄主逃避反应、其它天敌的竞争、寄主共生或共栖生物的存在、寄主植物、天敌自身的学习能力及其共生微生物等多种因素对寄生性天敌昆虫的寄主适应性可产生影响。展望了多寄主型寄生性天敌昆虫对新寄主资源的拓展利用能力和适应性在生产上的可能应用前景和途径,以期为明确天敌与寄主间的互作关系,人工驯化寄生性天敌昆虫增强对靶标害虫的控制作用,合理利用天敌提高生物防治效率提供新的思路和理论支持。     

梨星毛虫在甘肃陇东地区的生活史及寄生性天敌

梨星毛虫 Illiberispruni Dyar是陇东仁果重要害虫。 1 986年田间采集梨星毛虫老熟幼虫1 870头 ,进行室内阶段性饲养观察生活史和寄生性天敌。结果报导如下。1　生活史观察1 .1　梨星毛虫蛹期 7～ 1 4天 ,平均 1 0 .9天。羽化期 6月 2 1日～ 7月 1 0日 ,羽化率 72 .9% ,前期雄蛾占绝对优势 ,雌雄比 1∶ 1 .3 ;后期雌蛾占绝对优势 ,雌雄比 1∶ 0 .6。高峰期 6月 2 4～2 9日 ,其羽化量占 70 .3 %。每天有 2个羽化高峰 ,主要是 6～ 8时 ,其次是 1 8～ 2 0时。1 .2　雄蛾期 3～ 1 0天 ,平均 6.2天。雌蛾期 4～ 1 1天 ,平均 7.6天。交尾前期短促…     

美洲斑潜蝇及其寄生性天敌的生态位

通过调查美洲斑潜蝇及其主要寄生性天敌冈崎姬小蜂Neochrysoclaris okazakii Kamijo,芙新姬小蜂Neochrysoclaris formosa Westood和攀金姬小蜂Chrysocharis petheus Walker的时间和空间生态位,测定出生态位宽度,重叠和比例相似性,在生态位测定的基础上,按生态位的理论观点,探讨了寄生性天敌在美洲斑潜蝇综合治理中的控制作用。     

黑尾叶蝉寄生性天敌的初步调查

1981年5-10月,在闽北沙县洋枋,对稻田黑尾叶蝉几种主要寄生性天敌的生物学特性进行初步调查,并对保护利用的途径作初步探讨。     

寄主植物-蚜虫-天敌三重营养关系的化学生态学研究进展

综述了寄主植物－蚜虫－天敌三重营养关系的化学生态学研究,重点阐述了3个研究热点：①植物挥发性物质在蚜虫及其天敌选择寄主行为过程中的作用;②蚜虫信息素和蜜露对蚜虫天敌寄主选择行为的影响;③植物挥发性物质对蚜虫信息系作用的影响。对寄主植物－蚜虫－天敌三重营养关系的全面了解,将为蚜虫的综合治疗提供新思维。     

繁育寄主对稻螟赤眼蜂寄生行为及寄生能力的影响

【目的】繁育寄主影响赤眼蜂的生物学特性,为明确米蛾 Corcyra cephalonica (Stainton)卵繁育的稻螟赤眼蜂 Trichogramma japonicum Ashmead是否和二化螟Chilo suppressalis (Walker)卵繁育稻螟赤眼蜂在防治二化螟上有差别,及田间用米蛾卵作为稻螟赤眼蜂续代寄主的可行性,本实验观察了羽化自不同寄主的稻螟赤眼蜂的寄主选择和寄生行为,研究了两种繁育寄主对稻螟赤眼蜂寄生能力的影响,为田间防治水稻螟虫提供参考信息。【方法】室内利用选择试验观察了由米蛾卵和二化螟卵繁育出的稻螟赤眼蜂对两种寄主的选择趋性及在两种寄主上的寄生行为和寄生能力,统计了羽化子代蜂的寿命。【结果】由二化螟卵繁育的稻螟赤眼蜂表现出了对二化螟卵的选择偏好,而米蛾卵繁育的稻螟赤眼蜂在米蛾卵和二化螟卵间没有表现出寄主选择偏好。寄主搜寻时间不受繁育寄主及供试寄主的影响,卵表探测时间和穿刺及产卵时间不受繁育寄主的影响,但同一寄主繁育的稻螟赤眼蜂在米蛾卵上的卵表探测时间显著长于在二化螟卵上的卵表检测时间。除二化螟卵繁育蜂寄生二化螟卵时的寄生率（36.95%）和羽化率（45.68%）较低外,米蛾卵繁育蜂寄生米蛾卵或二化螟卵以及二化螟卵繁育蜂寄生米蛾卵等3组处理间的寄生率、羽化率均无显著差异,各处理组间子代蜂寿命也无显著差异。【结论】繁育寄主影响稻螟赤眼蜂的寄主选择和寄生能力,但不影响寄生蜂搜寻寄主的能力和寄生行为。     

黑刺粉虱及其天敌的研究

黑刺粉虱Aleurucamhus spiniferus Quaint．是柑桔、茶树等经济作物的重要害虫。福建一年发生4-5代,闽北、闽中发生4代,世代重叠。主要以若虫在柑桔等叶背越冬,越冬若虫于翌年2月间开始化蛹(伪蛹),4月间成虫羽化并产卵。各世代若虫发生期为第一代4月上旬至6月上旬;第二代6月中旬至7月下旬;第三代7月中旬至9月上旬;第四代9月中旬至翌年3月,11月进入越冬期。一年中以6-9月为发生为害高峰期。黑刺粉虱的寄生性天敌和捕食性天敌资源丰富,蛹期被寄生率甚高,对该虫的综合治理可以生物防治为主要措施。     

二化螟水稻类群和茭白类群成虫产卵与幼虫寄主选择行为的比较研究

实验室木箱条件下进行的二化螟水稻类群与茭白类群成虫产卵选择性试验结果表明,两类群在水稻与茭白上所产的卵块和卵粒的分布及孵化率无显著差异;但均有将不能孵化卵产在非本寄主上的倾向．通过Y形嗅觉仪进行的幼虫寄主选择行为的试验结果显示,除茭白类群1龄幼虫对水稻与茭白的趋性分别为30．00％与66．67％,有显著差异(P≤0．05)外,1龄幼虫对两寄主组织的趋性无显著差异;对水稻与茭白叶片、叶鞘的趋性反应中,水稻类群4龄、6龄幼虫对叶片,2龄、4龄幼虫对叶鞘差异显著,而茭白类群2—6龄幼虫均差异显著(P≤0．05)．研究结果表明,两类群已开始种下分化,其中茭白类群对本寄主的专化程度大于水稻类群。     

蜜露对天敌昆虫生长繁殖及搜寻行为的影响

已有研究表明:同翅目昆虫蜜露对一些天敌昆虫有着特殊的作用。一方面,蜜露可用来补充营养,从而促进天敌若虫死亡率下降、成虫寿命延长以及繁殖力提高;另一方面,蜜露作为天敌搜寻行为的信息物质。而人工蜜露在很多情况下对部分天敌也具有上述2方面的作用。文章就此内容的研究进展作一概述,以期促进蜜露在天敌昆虫人工饲养、害虫综合防治以及其他方面发挥作用。     

Differential attraction of parasitoids in relation to specificity of kairomones from herbivores and their by-products

Infochemicals are used by foraging parasitoids in the host selection process from habitat preference until host recognition. Kairomones from the herbivore host plays a vital role in the attraction of parasitoids, particularly in the micro-habitat. Parasitoids are specifically attracted to their respective herbivore species even when different herbivores are present on the same plant. Chemicals emitted from different stages of host （eggs, larvae, pupae, adult）, host by-products （e.g., frass, exuviae, mandibular gland secretions, defense secretions etc.）, or intra-specific infochemicals （pheromones） can be main signals for the parasitoids. Parasitoids can differentiate between host and non-host, between different hosts and host stages by perceiving specific volatile and contact kairomones from the host itself, host along with its by-product, by-products alone or intra-specific infochemicals; of which frass （by-product） and intra-specific infochemicals are the most reported ones. Adult and larval parasitoids have been reported to be attracted to kairomones of their target stage or byproduct of their host. Pupal parasitoids have been found to utilize kairomones from the preceding host stage while egg parasitoids are known to exploit a variety of host infochemicals, for example, either from eggs themselves or other non-target host stages, especially adults and adult-related by-products. The kairomonal chemicals identified so far include various groups, but mainly hydrocarbons. A high degree of host specificity and host acceptance is important for the parasitoids as any mistake may result in the loss of fitness.     

Differential attraction of parasitoids in relation to specificity of kairomones from herbivores and their by‐products

Infochemicals are used by foraging parasitoids in the host selection process from habitat preference until host recognition. Kairomones from the herbivore host plays a vital role in the attraction of parasitoids, particularly in the micro‐habitat. Parasitoids are specifically attracted to their respective herbivore species even when different herbivores are present on the same plant. Chemicals emitted from different stages of host (eggs, larvae, pupae, adult), host by‐products (e.g., frass, exuviae, mandibular gland secretions, defense secretions etc.), or intra‐specific infochemicals (pheromones) can be main signals for the parasitoids. Parasitoids can differentiate between host and non‐host, between different hosts and host stages by perceiving specific volatile and contact kairomones from the host itself, host along with its by‐product, by‐products alone or intra‐specific infochemicals; of which frass (by‐product) and intra‐specific infochemicals are the most reported ones. Adult and larval parasitoids have been reported to be attracted to kairomones of their target stage or byproduct of their host. Pupal parasitoids have been found to utilize kairomones from the preceding host stage while egg parasitoids are known to exploit a variety of host infochemicals, for example, either from eggs themselves or other non‐target host stages, especially adults and adult‐related by‐products. The kairomonal chemicals identified so far include various groups, but mainly hydrocarbons. A high degree of host specificity and host acceptance is important for the parasitoids as any mistake may result in the loss of fitness.     

Overwintering microhabitat selection by an Endoparasitoid (Hymenoptera: Aphidiidae): Induced phototactic and thigmokinetic responses in dying hosts

Aphidius nigripesAshmead, an endoparasitoid of the potato aphid, Macrosiphum euphorbiae(Thomas), not only has the ability to modify host behavior, but does so differently depending on its physiological state. A previous study indicated that just prior to death, parasitized aphids that contain diapausing parasitoid larvae leave the host plant to mummify in concealed sites, while those containing nondiapausing parasitoids generally remain on the plant. This study explored the proximal factors involved in the selection of an overwintering microhabitat by a host containing a diapausing A. nigripeslarva. Parasitized aphids showed negative phototaxis, thigmokinesis, and chose a dark rather than a light-colored substrate when seeking a site to mummify. However, their behavior was not influenced by either gravity or the presence of another mummy. The combined effects of these behavioral patterns would result in dormant parasitoids overwintering in sheltered sites, thereby reducing the negative effects of adverse climatic conditions and the actions of natural enemies. The utilization of these proximal cues may also enhance parasitoid, survival by reducing aphid wandering time prior to mummification.     

Interactions between the egg and larval parasitoids of a gall-forming midge and their impact on the host

1. The gall‐forming midge Rhopalomyia californica was exposed experimentally to parasitism and predation during only the egg stage, during only the larval stage, during neither stage, or during both stages. 2. The combined action of natural enemies that attack during both the egg stage and the larval stage led to the lowest number of midges and total insects (midges + parasitoids) in the next generation, and the highest percentage parasitism. 3. The larval parasitoid killed a large fraction of hosts without producing new parasitoid offspring, while there is some indication that the egg parasitoid on its own tended to produce the most parasitoid offspring. The contrasting implications of host mortality versus parasitoid production for biological control are discussed. 4. Exposure to larval parasitoids resulted in a reduction in the number of egg parasitoid offspring produced, but exposure to the egg parasitoid did not affect the number of larval parasitoid offspring produced significantly.     

Influence of environmental conditions on patch exploitation strategies of parasitoids

In patchy environments, patch-leaving decision rules are a keycomponent of the foraging behavior of parasitoids that haveto share their searching time between the different host patchesto optimize the number of ovipositions. It has been experimentallyshown that one of the proximate cues involved in patch-leavingdecision is the number of ovipositions performed by the parasitoidwhile in the patch. Ovipositions can have either a decrementalor an incremental effect on the patch residence time dependingon parasitoid species. Previous theoretical studies have suggestedthat environmental conditions and the ability of parasitoidsto reliably estimate the number of available hosts on a patchwhen entering it should influence how patch departure dependson ovipositions. We developed an individual-based model to testa large variety of patch-leaving decision rules in differentenvironmental conditions. This model includes a more realisticrepresentation of individual acquisition of information thanprevious theoretical work. In accordance with previous results,we show that the best use of information depends on environmentalconditions. Moreover, we identify the environmental factorsthat have a decisive influence on the most appropriate typeof rule (incremental or decremental). Decremental mechanismsare most efficient only in restricted conditions characterizedby a large number of patches and few parasitoids. The sensitivityof decision rules to frequency-dependent processes was testedby numerical invasibility experiments. Rare mutants using anyalternative rule never outperform populations using a high-performancerule. Incremental rules seem to be more sensitive than decrementalones to frequency-dependent processes.     

Evolutionary patterns of host utilization by ichneumonoid parasitoids (Hymenoptera: Ichneumonidae and Braconidae)*

The four major biological strategies of ichneumonoid parasitoids, koinobiont and idiobiont, ecto-and endoparasitism, are discussed and the evolutionary radiations of the two families Ichneumonidae and Braconidae compared in an attempt to relate differences in patterns of host utilization to differences in evolutionary history. The most primitive members of both families are idiobiont ectoparasitoids of hosts concealed in plant tissue. Idiobiont ectoparasitic braconids are all still primarily associated with such hosts, but idiobiont ectoparasitic ichneumonids have radiated to attack hosts in other situations, such as in aculeate nests or in cocoons. A shift in emphasis between the behavioural steps, host habitat location and host location, is envisaged as being important in such evolutionary change. Idiobiont endoparasitism is postulated as having arisen amongst ectoparasitoids attacking cocooned hosts, as an adaptation that allows them to exploit pupae and puparia in relatively exposed positions; it is a fairly common strategy in the Ichneumonidae, but virtually unknown in the Braconidae. Koinobiosis is perceived as having evolved in association with hosts which feed in a relatively weakly concealed position, but pupate in a more secluded and safe location. The strategy is advantageous as it allows a parasitoid to oviposit on an easily discoverable host, but to use the host's pupation concealment to complete its own development. The evolution of koinobiosis has allowed parasitoids to exploit hosts that feed in exposed positions, and to attack hosts at a younger and numerically more common stage in the host's life cycle. Koinobiont ectoparasitism is envisaged, in some braconid and ichneumonid groups, to occupy an evolutionary transitional position between idiobiosis and endoparasitic koinobiosis; only in the Ichneumonidae have large radiations of koinobiont ectoparasitoids occurred. Endoparasitic koinobiosis is hypothesized as having arisen in the Braconidae in association with lepidopterous/coleopterous hosts, whilst in the major lineage of endoparasitic koinobiont ichneumonids, this habit is hypothesized as having arisen in association with symphytan hosts. The great majority of braconids are koinobiont endoparasitoids, but only about 50% of the Ichneumonidae have this habit. Very few koinobiont braconids develop as endoparasitoids of hymenopterous hosts, although many endoparasitic ichneumonids attack Hymenoptera. However, lineages of the Braconidae have radiated to exploit adult insects and exopterygote nymphs; ichneumonids do not utilize such hosts.     

Marking Behavior and Discrimination of Concealed Hosts by the Ectoparasitoid, Dinarmus basalis Rond. (Hym. Pteromalidae)

The parasitoid species, Dinarmus basalis, attacks bruchid beetle larvae concealed within hard seeds. Female wasps are able to discriminate the quality of their host but the position in the concealed host system where this discrimination takes place remains unclear. Under laboratory conditions, we investigated whether the cues were detectable: (1) at a medium or short distance from the seed, (2) on the seed, or (3) within the seed, at the point of contact with the host. In particular, we investigated whether internal or external markings are applied by the parasitoid and then recognized in a subsequent encounter or by a conspecific encountering the host. Detailed behavioral observations did not provide evidence of markings being applied onto the seed or used, but showed that host discrimination occurred on the basis of internal cues. The lack of evidence of external markings is unexpected and raises the question as to which circumstances in the parasitoid's ecology and life history could result in such a lack not causing a reduction of fitness.     

玉米螟卵期寄生性天敌调查

在玉米螟卵期的寄生性天敌中,玉米螟赤眼蜂占93．51％,其它寄生蜂仅占6．49%．玉米螟赤眼蜂是卵期的优势蜂种。年度之间玉米螟卵的被寄生草差异较大。逐步回归分析表明,第2代玉米螟卵的被寄生率与第1代玉米螟卵发生量(X1),6月份温雨系数(X2),第2代玉米螟卵发生量(X2),7月上旬雨量(X4)和7月中旬雨量(X3)有极显相关(X1、X4为主要影响因于)。第3代玉米螟卵的被寄生率与7月上旬雨量(X2)、7月下旬雨日(X2)、8月上旬气温(X3),8月上旬雨量(X4)和8月下旬雨量(X5)有极显相关。由此可见,第1代卵发生量大,上代次卵发生期多雨,当代次卵发生期前少雨,当代次卵发生期多雨,有利于赤眼蜂寄生,玉米螟卵被寄生率提高。     

An airflow olfactometer for measuring olfactory responses of hymenopterous parasitoids and other small insects

ABSTRACT. A new type of airflow olfactometer is described, and results given of experiments using it to measure behavioural olfactory responses of hymenopterous parasitoids. Compared with Y-tube olfactometers it shows several advantages. In its exposure chamber four separate abutting odour fields are presented so that the test insect can readily enter and re-enter them. More than one odour (or different concentrations of one odour) can be tested at the same time, thereby providing complex preference test situations. The various behavioural measures that can be assessed in the apparatus are examined and discussed.     

Delayed emergence and the success of parasitoids in biological control

Delayed emergence, a life history feature of many insects living in unpredictable environments, can have major consequences for the dynamics of host–parasitoid interactions, which vary according to their physiological interactions. We studied, through simple modeling, the significance of prolonged diapause on the suppression levels achieved by parasitoids and illustrate our case with a system involving a major forest pest, the woodwasp Sirex noctilio and two of its parasitoid species that have been introduced into different geographical regions through classical biological control programmes. Our findings suggest that the physiological relationship between parasitoid and host delayed emergence patterns may help understand observed variable success in several bio-control programs. We conclude that for given environments, host delayed emergence and the way in which parasitoids deal with it, should be included in the list of selection criteria of natural enemies of many pests, especially those affecting forests.